The present invention relates to a method of manufacturing a semiconductor device, particularly, a technology effective when applied to the manufacture of a semiconductor device including an image pickup element.
Image pickup elements (imaging devices) to be used for digital cameras and the like are each comprised of, for example, a plurality of pixels arranged in matrix form and including a photodiode that detects light and generates charges. As the configuration of a pixel, known is that having the photodiode, a transfer transistor for outputting the charges to peripheral elements, and the peripheral elements, for example, for amplifying signals. The layout of the photodiode formed on the main surface of a semiconductor substrate is defined by an element isolation region surrounding the periphery of the photodiode. As a method of forming the element isolation region, known is a method of forming a trench in the main surface of the semiconductor substrate, filling the trench with an insulating film, and thereby forming the element isolation region made of the insulating film.
Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2005-142319), Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2008-60383), and Patent Document 3 (Japanese Unexamined Patent Application Publication No. 2006-59842) describe removal of damage and metal contamination generated in an element isolation trench. Patent Document 4 (Japanese Unexamined Patent Application Publication No. 2007-67379), Patent Document 5 (Japanese Unexamined Patent Application Publication No. 2007-288136), and Patent Document 6 (Japanese Unexamined Patent Application Publication No. 2009-277722) describe implantation of boron into side walls of the trench.